1. Field
The following description relates to a communication system. More particularly, the description relates to a communication system using a modulation scheme and a coding scheme.
2. Description of the Related Art
Currently, various communications schemes are used to achieve a high data transmission rate. However, the bit error rate increases as the data transmission rate increases when transmission power is limited. In addition, shadow zones may increase in urban areas as high frequency bands are used.
A relay station is required to solve problems due to shadow zones and to reduce the bit error rate, when the data transmission rate is increased.
However, the addition of a relay station to a communication system requires additional wireless resources because an additional time slot allocation is required for the relay station. As an example, when the relay station receives a message from a source node in a time slot and transmits the message to a destination node, two time slots are required. In other words, a single time slot is required by the source node to directly transmit the message to the relay station and another time slot is required for the relay station to transmit the message to a destination node. Consequently, when the relay station is added to the communication system, additional wireless resources are required for the relay station, overall performance of the communication system may be diminished.